The programme opened with the multi-millionaire star calling 11 audience members to the stage to tell them they had won the new cars from General Motors.

She then handed out gift boxes to the rest of the audience, saying one held keys to a 12th car.

At the count of three, the boxes were all opened and the ecstatic guests realised they were all winners, while Oprah jumped up and down, yelling: "Everybody gets a car! Everybody gets a car! Everybody gets a car!"

A spokesman for the programme - which has been the top daytime talk show in the US since 1989 - said: "We've never done a giveaway like this before."